A buddy of mine had one with the Saito 1.80 and 17x6 APC...it flew great, but if you want fuel economy, the 1.80 might not fit the bill for you?
Generally speaking, a twin won't make the same power as an equivelent size single.

Just a thought...how about an O.S. 1.60 maybe? Another flyin' buddy has one in a DP Extra, and it seems to pull it around well...